Author: Ian O'Neill

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Hello! My name is Ian O'Neill and I've been writing for the Universe Today since December 2007. I am a solar physics doctor, but my space interests are wide-ranging. Since becoming a science writer I have been drawn to the more extreme astrophysics concepts (like black hole dynamics), high energy physics (getting excited about the LHC!) and general space colonization efforts. I am also heavily involved with the Mars Homestead project (run by the Mars Foundation), an international organization to advance our settlement concepts on Mars. I also run my own space physics blog: Astroengine.com, be sure to check it out!

[/caption]“While my body was asleep, I think my soul rode on a triangular-shaped UFO and went to Venus.”

This might sound like a quote taken from the ramblings of a conspiracy theorist or the chant from someone who spent an hour too many at an Amsterdam coffee shop, but it wasn’t.

Actually, these are the words of the wife of the Japanese premier-in-waiting Yukio Hatoyama.

Mrs Miyuki Hatoyama might be married to a man Japan nicknames “The Alien,” but it looks like it’s not him who has dreams of an extraterrestrial nature…
If there’s one thing politicians must dread when they are voted into a position of power, it’s the past. Previous indiscretions, past conversations, old business that involved major campaign donors; all of these must keep many government ministers awake at night, worried that the media will dig up some dirt.

However, in the case of the soon-to-be prime minister of Japan (who won the recent elections with a landslide victory), it’s his 66-year old wife who wrote something last year in a book called Very Strange Things I’ve Encountered, that’s causing a stir. But through his wife’s own admission, Yukio Hatoyama is an open minded fellow and probably won’t be concerned about what the public may think of Miyuki’s book.

Very Strange Things documents Mrs Hatoyama’s experiences 20 years ago when a UFO picked her up and took her to Venus. “It was a very beautiful place and it was really green,” she observed.

If by “green” she actually means “dark brown,” and by “beautiful” she means “a tropical, bone crushing atmosphere, stuffed with poisonous gas and a landscape resembling hell,” then I think Miyuki really did fly there.

Naturally, after she had her joyride to Venus, Miyuki arrived back in bed, next to her now ex-husband who told her it was just a dream.

In addition to her night-time jaunts around the Solar System, Miyuki also partakes in a little solar feast every now and again. On a Japanese TV show earlier this year, Miyuki went into some detail about her spiritualistic beliefs.

“I also eat the sun,” she said on the program, closing her eyes, pulling pieces off an imaginary Sun. “Like this, hum, hum, hum. It gives me enormous energy […] My husband has recently started doing that too.”

This all seems like a lot of fun, but what does this mean for Japan? As noted by Keith Cowing over at NASA Watch, perhaps we’ll see a boost in JAXA (the Japanese space agency) funding. It might also go some way to explaining why there’s been a surge of interest in Japanese space solar power!

Things might go a little too far if we start seeing JAXA UFO patrols in low-Earth orbit, but for now, I suspect it’s going to be a rather flamboyant term in office for the Hatoyama’s…

[/caption]Decommissioning nuclear weapons is a good thing. But when our boldest space missions depend on surplus nuclear isotopes derived from weapons built at the height of the Cold War, there is an obvious problem.

If we’re not manufacturing any more nuclear bombs, and we are slowly decommissioning the ones we do have, where will NASA’s supply of plutonium-238 come from? Unfortunately, the answer isn’t easy to arrive at; to start producing this isotope, we need to restart plutonium production.

And buying plutonium-238 from Russia isn’t an option, NASA has already been doing that and they’re running out too…
This situation has the potential of being a serious limiting factor for the future of spaceflight beyond the orbit of Mars.

Exploration of the inner-Solar System should be OK, as the strength of sunlight is substantial, easily powering our robotic orbiters, probes and rovers. However, missions further afield will be struggling to collect the meagre sunlight with their solar arrays. Historic missions such as Pioneer, Voyager, Galileo, Cassini and New Horizons would not be possible without the plutonium-238 pellets.

So the options are stark: Either manufacture more plutonium or find a whole new way of powering our spacecraft without radioisotope thermal generators (RTGs). The first option is bound to cause some serious political fallout (after all, when there are long-standing policies in place to restrict the production of plutonium, NASA may not get a fair hearing for its more peaceful applications) and the second option doesn’t exist yet.

Although plutonium-238 cannot be used for nuclear weapons, launching missions with any kind of radioactive material on board always causes a public outcry (despite the most stringent safeguards against contamination should the mission fail on launch), and hopelessly flawed conspiracy theories are inevitable. RTGs are not nuclear reactors, they simply contain a number of tiny plutonium-238 pellets that slowly decay, emitting α-particles and generating heat. The heat is harnessed by thermocouples and converted into electricity for on board systems and robotic experiments.

RTGs also have astonishingly long lifespans. The Voyager probes for example were launched in 1977 and their fuel is predicted to keep them powered-up until 2020 at least. Next, the over-budget and delayed Mars Science Laboratory will be powered by plutonium-238, as will the future Europa orbiter mission. But that is about as far as NASA’s supply will stretch. After Europa, there will be no fuel left.

If plutonium-238 production is to be started again, a decision will need to be made soon. It will take eight years to start producing 5 kilograms of plutonium-238 per year, therefore any application for additional funding for plutonium-238 production for space exploration will need to be placed in next year’s budget.

[/caption]The Russian supply ship for the International Space Station successfully launched from Baikonur Cosmodrome in Kazakhstan at 2:37 pm EDT (10:37 pm Moscow time) on Thursday to carry 2.5 tonnes of supplies to the orbiting crew. Progress 33 will take over from Progress 32 that was filled with rubbish and unwanted instrumentation and de-orbited on May 6th, sent on its way to burn up over the Pacific Ocean on May 18th.

It seems the spaceship exchange went according to plan. Progress 33 launched, Progress 32 de-orbited and the space station is stocked until the next delivery.

However, a small village in South Siberia didn’t have such a harmonious evening; a chunk of the Progress rocket booster fell onto a house.

This time, local residents reported hearing two sharp cracks and then a crash when something fell on the roof of a two-storey apartment block. Immediately the emergency services were called and fire fighters found a 1×4 foot piece of metal. It has been confirmed that this piece of debris originated from the Progress rocket launched earlier that night.

Fortunately there were no injuries and no significant property damage.

Regardless, the Russian space agency appears to be concerned that somebody is out to get compensation. “There is only one fragment and the house is not within the calculated area of possible debris fallout,” said a space agency spokesman. “In any case, there are no casualties or material damage, according to our information.”

The agency added that locals may have found the rocket debris elsewhere, transported it to Baranovka, put it on the roof and then claimed it fell from the sky.

To be honest, so long as there are no faked concussions or claims of “pain and suffering”, I suspect the residents won’t be suing for damages. (As there doesn’t appear to be any damage.)

I hope they get to keep the rogue bit of rocket though. That would make a great trophy in the village bar!

Panspermia is a hypothesis that suggests life isn’t an Earth-only affair. The seeds of life may have spread throughout the Solar System and beyond via chunks of rock or comets, encountering planetary bodies, transporting spores or bacteria to other worlds. In short, we could be living in a cosmic ecosystem linked through simple interplanetary vagabond bacteria.

However, panspermia remains in the realms of speculation as we haven’t found any examples of extraterrestrial life (so far), let alone the possibility that life may be roaming freely through the vacuum of space. But panspermia as a life-spreading mechanism remains a possibility.

Now, famous physicist and futurist Freeman Dyson has come forward with an idea about what we should be looking for during the search for extraterrestrial life. Dyson believes the search for ET is flawed, as we are looking for what we deem to be probable lifeforms; perhaps we should be looking for detectable lifeforms.

And what’s one of the most detectable forms of life we know of? Flowers. What’s more, these flowers may have spread as far afield as the Kuiper belt and the Oort cloud…
“I would say the strategy in looking for life in the universe [should be] to look for what’s detectable, not what’s probable,” Freeman Dyson said on Saturday at a conference in Cambridge, Massachusetts.

“We have a tendency among the theorists in this field to guess what’s probable. In fact our guesses are likely to be wrong,” Dyson said. “We never had as much imagination as nature.”

We only have nature on Earth to learn from; this is the only life we know. There’s a certain set of rules life on Earth lives by (i.e. life exists here because it has evolved to adapt to temperatures, pressures and availability of sustenance), there’s a possibility that extreme forms of life could exist on other planets, but until we find this life, we don’t know what rules that life lives by. So scientists will logically look for probable forms of life.

However, Dyson points out that we should look for the most detectable forms of life. And one such example is the flower.

The Arctic Poppy (pictured top) is a flower that forms a parabolic shape. This shape maximizes the light that reflects off the inside of the petals so the interior of the plant can utilize solar energy. In the Arctic, often light is at a premium, so the flower has adapted to make full use of the Sun it can receive. From a distance, these mini solar collectors reflect a lot of light, and they should create a good indicator that plant life is thriving.

Now if we think about the icy Jovian moon Europa, it is thought to contain a liquid water ocean beneath a thick crust of ice and astrobiologists are very keen to send a mission to probe this potential life-harbouring habitat. Unfortunately, it might be hard for any robotic submersible to drop into the depths of this sub-surface sea as the ice could be up to 100 km thick in places.

So Dyson suggests that perhaps we should send an orbiter to Europa, not to look for an indication of life in the sub-surface ocean, but to look for more detectable signs of life, like flowers on the surface of the icy planet. After all, many types of plants grow in extremely cold locations on Earth, perhaps extreme plants thrive on Europa’s surface too?

“You can imagine once you have flowers that get nourished from below, they could evolve in the direction of being independent,” said Dyson.

He points out that once these plants become established on a body such as Europa, there’s the possibility that the seeds of these plants become distributed around the Solar System. If we ignore the fact that “life as we know it” requires a certain amount of solar energy to survive (at an orbital distance that is neither too close or too far from the Sun; otherwise known as the “Goldilocks Zone”), plant life that can survive in astonishingly cold temperatures may have adapted to live as far afield as the Kuiper Belt (near the orbit of Pluto), or beyond.

These are fair points, but I’d be cautious about trying to imagine the unimaginable. Although we need to keep an open mind as to what extraterrestrial life might look like, and optimize our search for detectable signs of life, we need to remember that the only form of life we know of and can study is here on Earth, and it remains a good starting point when looking for life on other planets.

Still, the thought of Arctic Poppies growing on Europa is an interesting idea, as it is possible, if panspermia is proven, that the Europa Arctic Poppies could be a descendent of their terrestrial counterparts…

The Solar System often throws up surprises for astronomers, but the recent discovery of a 2- to 3-km wide asteroid called 2009 HC82 has sent observers in a spin. A retrograde spin to be precise.

This particular near-Earth asteroid (NEO) should have already been spotted as it has such a strange orbit. It is highly inclined, making it orbit the Sun backwards (when compared with the rest of the Solar System’s planetary bodies) every 3.39 years. What’s more, it ventures uncomfortably close (3.5 million km) to the Earth, making this NEO a potentially deadly lump of rock…
2009 HC82 was discovered on April 29th by the highly successful Catalina Sky Survey, and after independent observations by five different groups, it was determined that the asteroid has an orbit of 3.39 years and that its orbit is very inclined. So inclined in fact that the asteroid’s orbit takes it well out of the Solar System ecliptic at an angle of 155°. Inclined orbits aren’t rare in themselves, but if you find an asteroid with an inclination of more than 90°, you are seeing a very rare type of object: a retrograde asteroid.

The last time I wrote about a retrograde asteroid was back in September 2008 (Kuiper Belt Object Travelling the Wrong-Way in a One-Way Solar System), when a University of British Columbia researcher spotted a rather unique retrograde Kuiper belt object (called 2008 KV42) that had a large looping orbit with an inclination larger than 90°. It was nicknamed “Drac” after Dracula’s ability to walk on walls.

2009 HC82 is therefore not only rare, it is also very strange. It orbits the Sun the wrong way (therefore making it very inclined), it is a potentially hazardous NEO (it is smaller than the 10 km asteroid that is attributed to wiping out the dinosaurs, but it would cause significant devastation on a global scale if it did hit us) and it is very eccentric.

The orbit of 2009 HC82 (NASA)

All these orbital components have led to speculation that 2009 HC82 is in fact a “burnt out” comet. Comets originate from the Oort Cloud, a theoretical region cometary nuclei that occasionally gets nudged by gravitational disturbances when stars pass by. The Oort Cloud is not restricted to a belt along the ecliptic (like the asteroid belt or the Kuiper belt), it encapsulates our Solar System. Therefore, this may explain 2009 HC82’s bizarre trajectory; it was a comet, but all the ice has vaporized, leaving a rocky core to fling around the Sun on a death-defying orbit, buzzing the inner Solar System.

Brian Marsden of the Minor Planet Center agrees that some retrograde asteroids could be burnt-out comets. The size and shape of the new asteroid’s orbit “is very like Encke’s comet except for inclination,” he said, but the only difference is the fact that 2009 HC82 has no cometary tail.

More observations are needed before a definitive conclusion can be made, but Marsden is confused as to why this object has not been discovered before now. “It should have been easily observable in 2000,” says Marsden. “Why wasn’t it seen then?”

In 1979, the huge Chicxulub crater, measuring about 180 km (112 miles) in diameter, was discovered on the northern Yucatan Peninsula, Mexico. Scientists made the obvious conclusion that something rather large had hit the Earth in this location, probably causing all kinds of global devastation 65 million years ago. At around the same time, 65% of all life on the face of the planet was snuffed out of existence. The dinosaurs that roamed the planet up to that point were no more.

The timing of asteroid impact and the time of the mass extinction was too much of a coincidence to be ignored. When particles from the asteroid impact were discovered just below the Cretaceous-Tertiary (K-T) boundary, there was a strong causal link: the effects of the asteroid impact had driven the dinosaurs to extinction.

However, a problem with this theory has come to light. It turns out the Chicxulub impact may pre-date the K-T boundary by 300,000 years…
A number of scientists have disagreed with the theory that the Chicxulub impact caused the death of the dinosaurs 65 million years ago, and this newest research appears to show the two events may not be linked after all.

Gerta Keller of Princeton University in New Jersey, and Thierry Adatte of the University of Lausanne, Switzerland, are set to publish this new work in the Journal of the Geological Society today, using data from the analysis of sediment from Mexico to prove the asteroid impact pre-dated the K-T boundary by as much as 300,000 years.

“We know that between four and nine meters of sediments were deposited at about two to three centimeters per thousand years after the impact,” said Keller. “The mass extinction level can be seen in the sediments above this interval.”

This means that the mass extinctions appeared to take place a long time after the impact. However, impact-extinction advocates point out that this inconsistency in sediment data is probably down to sediment disruption by tsunamis and geological upheaval immediately after the impact.

According to Keller, there is no indication that this could be the case. Deposition of impact sediment occurred over a huge time period, not the hours or days deposition would have taken if a tsunami affected sedimentary records.

Another problem with the impact extinction theory is that the Chicxulub impact may not have had the radical extinction effect on plants and animals as we previously thought. The researchers found a total of 52 fossilized species that appeared to be happily living before the layer of impact sediment… and the same 52 species appeared to by happily living after the layer of impact sediment.

“We found that not a single species went extinct as a result of the Chicxulub impact.” — Gerta Keller

Although this is some very interesting research, sure to turn dinosaur extinction theory on its head, if an asteroid didn’t kill the dinosaurs, what did?

Keller points the finger at volcanic activity. Massive amounts of dust and gas was released from eruptions at the Deccan Traps in India 65 million years ago, possibly plunging the planet into a prolonged period without Sun.

Update: With any scientific debate, there are details behind new research that may not be immediately apparent. As Ethan Siegel highlights in a recent ScienceBlogs article (What Wiped Out The Dinosaurs?, April 27th), the evidence for an asteroid impact wiping out the dinosaurs is overwhelming. Just because there appears to be a discrepancy in the location of impact sediment and K-T boundary does not mean the impact-extinction theory is wrong in any way. Keller’s research is an interesting investigation, worthy of further study, but this doesn’t change the fact that huge global damage would have been caused by the Chicxulub impact. This remains the prime candidate as to why the dinosaurs were suddenly made extinct 65 million years ago.

380,000 years after the Big Bang, the Universe cooled from being a hot soup of plasma, to a temperature where protons and electrons could combine to form atoms. This calm period of neutral hydrogen in universal history didn’t last for long however. The neutral hydrogen atoms were ripped apart once more, by a mechanism that would go on to reionize the entire Universe, a process that eventually ended a billion years after the Big Bang.

It is thought the first stars that formed prior to the reionisation epoch probably pumped out some fierce ultraviolet radiation, ionizing the neutral hydrogen, but a new (controversial) theory has been put forward. Did dark matter have a role to play in the reionisation the Universe?
As 85% of the Universe is composed of a type of matter we have yet to fully account for, it seems only natural that scientists would be looking into the possibility that dark matter had a role to play soon after the Big Bang. Although scientists are fairly confident that the reionisation period was driven by the emissions from the very first stars, there are some observational factors that could suggest dark matter annihilation might have had a role to play in the evolution of the Universe.

This is according to Dan Hooper and Alexander Belikov from Fermilab in Batavia, Illinois, in any case. In their theory recently published, the researchers examine the physics behind dark matter annihilation as the mechanism that drove the reionisation epoch.

In Hooper and Belikov’s work, they focus on dark matter that is theorized to have clumped together under gravitational attraction as the Universe cooled during the neutral hydrogen era (known as the “Dark Ages” – the Universe would have been opaque due to lack of stars and lack of electromagnetic radiation). When the dark matter during this time clumped, it is predicted to annihilate. During dark matter annihilation, high energy gamma-rays are predicted to be generated. Where gamma-radiation goes, ionization of matter is sure to follow.

By their reasoning, rather than emissions from stars that may have been forming at the start of the reionisation epoch, a far more potent ionization mechanism could have flooded the Universe. However, some scientists are skeptical of this idea.

“We have no evidence yet that any dark matter has ever annihilated,” says Charles Bennett, principal investigator on NASA’s WMAP satellite, which has been studying the reionisation epoch. “I am not saying it is wrong, but it sounds a bit too contrived for me to eagerly accept it.” Bennett sees the dark matter argument as one mystery (reionisation) being explained by another mystery (does dark matter even annihilate?).

For now, the idea that dark matter may have been the underlying mechanism ionizing our Universe remains highly theoretical. But Hooper is eager to study the data from ESA’s upcoming Planck mission as this observatory will be able to study how reionisation proceeded with time. “The time signature of dark matter reionisation will be different from that brought about by stars,” says Hooper.

It’s been a worrying month for the health of Mars Expedition Rover Spirit. Two weeks ago, the embattled robot failed to wake up after three successive communication sessions, and then over the Easter weekend (April 12th and 13th), mission HQ noticed the rover had rebooted its systems at least twice during use of the high-gain antenna. The same thing happened on April 18th. In addition to this, Spirit has been suffering bouts of what seems to be an ‘electronic amnesia’, where the onboard computers have failed to record data onto their flash memory.

Today however, it would appear Spirit is still operational after over two weeks of remaining planted in the same position. It managed to enact commands sent from NASA to start driving once more, trundling 1.7 metres over the Martian regolith. She hasn’t given up the good fight quite yet…
Since when have electronics on Earth ever lasted more than five years? I always seem to hit a two-year wall with my laptops when something nasty happens to the hardrive and/or motherboard (usually a day or two after the warranty runs out). But when we talk about the computers on board the Mars Expedition Rovers (MER), these electronics aren’t in the snug safety of my office; they are on the surface of an alien planet, dealing with extremes in temperature, high energy particles and copious amounts of dust. What’s more, the rovers were only designed to operate for a few months and yet they are still going strong, five years later. It’s the NASA mission that just keeps on giving.

I think this is what makes the MER mission so impressive for me. Not only are Spirit and Opportunity still operational, they are operating 20 times longer than their designated lifetime and they are notching up a very healthy odometer count. Their cumulative distance travelled is not measured in metres, or kilometres; it’s measured in tens of kilometres. They are giving us an unprecedented insight to the Martian surface, information that will shape our understanding of planetary science for generations to come.

But like any planetary mission, times can be tough, and both rovers have been tested to their engineered limits. Unfortunately, Spirit has been hit by a few more setbacks than Opportunity, but NASA has been able to find workarounds for each problem. The Mars Science Laboratory has a lot to live up to, I wonder if the MER mission will still be operational when the MSL finally touches down? Perhaps the next generation rover will have a robotic welcoming party!

The most recent issue for Spirit has been the flash memory problem. Flash memory helps the rovers store data even when they are powered down, but when the little rover forgets to actually store the data on the flash memory, something is obviously awry. In an attempt to make sure the rover can still take commands and to see if the computer problems persist, NASA ordered Spirit to travel 1.7 metres toward a target 150 metres away. All seems to be going well so far.

“We expect we will see more of the amnesia events, and we want to learn more about them when we do,” said JPL’s Sharon Laubach, chief of the rover sequencing team, which develops and checks each day’s set of commands.

“We decided not to wait until finishing the investigations before trying to drive again. Given Spirit’s limited power and the desire to make progress toward destinations to the south, there would be risks associated with not driving.”

Hopefully keeping the rover mobile will help NASA troubleshoot the recent computer problems, but so far, she’s still rolling over the Martian dirt…

A collection of very odd white dwarfs have been discovered in a local globular cluster. Twenty-four white dwarfs (18 of them are new discoveries) have been spotted. Although these degenerate stars aren’t exactly an uncommon (they are the small sparkling remnants left over after star death), this particular set are unique; they are made from helium, rather than the “standard” carbon and oxygen. And they are small, even smaller than the smallest dwarfs.

How did this dense cluster of old stars evolve? It turns out their stellar material is being stolen, stifling their development…
“Helium-core white dwarfs have only about half the mass of typical white dwarfs, but they are found concentrated in the center of the cluster,” said Prof. Adrienne Cool, from San Francisco State University, in a paper to be published in the Astrophysical Journal in July. “With such low masses, the helium-core white dwarfs ought to be floating all around the cluster, according to theory. The fact that we find them only in the central regions suggests that they have heavy companions — partner stars that anchor them to the cluster center.”

The Hubble observations show 18 previously undiscovered helium-core white dwarfs (Jay Anderson / Space Telescope Science Institute)Cool and co-author Rachel R. Strickler believe they are seeing a case of stellar plasma theft by companion binary stars in the NGC 6397 cluster, approximately 7,200 light years away. These binary partners not only anchor these strange-looking white dwarfs in the centre of the cluster, they also have a huge role to play during the dwarfs evolution.

Before a white dwarf emerges from a planetary nebula, the parent star will have gone through the red giant phase (a phase our Sun is expected to go through in 4-5 billion years time). If this red giant has a binary partner (which seems to be the case of the 24 white dwarfs in this study), the outer layers of the puffed-up giant will be stripped away by the partner, stifling the red giant’s evolution. As mass is lost, the giant never gets the chance to burn helium and then progressively heavier elements such as carbon and oxygen in and around its core. Helium then becomes the key component of these smaller-than-usual white dwarfs.

“This is the first time that helium-core white dwarf stars have been discovered in partnerships with other white dwarfs in a globular cluster,” Cool said. “This large sample allows us to answer questions about the mass and nature of the partner stars, and the prevalence of these kinds of binaries in the globular cluster.”

Binary stars are known to affect their partners fairly radically, they are even known to slow or even stop the development of black holes, stripping the outer layers of the dying star, stifling black hole development by removing mass from the parent star. However, not all questions have been answered.

From Cool’s calculations, 5% of the stars found in NGC 6397 should end their lives as dim helium-core white dwarf stars, but after studying Hubble data, many of these tiny dwarfs are missing. “It’s possible that these helium-core white dwarfs cool so slowly that they haven’t had time to get very faint yet,” Cool said.

There remains the possibility that the oldest binaries containing helium-core white dwarfs have actually been destroyed by interactions with other stars in the cluster. Regardless, this is a fascinating area of study. To understand how these ancient stars evolve will not only aid the development of globular cluster models, but it will provide an invaluable insight to how binary stars influence their partners.

This strange image was captured by the High Resolution Imaging Science Experiment (HiRISE) camera on board NASA’s Mars Reconnaissance Orbiter (MRO) on April 11th. At first it looked like a classic example of my early camera days without a tripod; most of the photos I took were blurry or out of focus (due to my less-than-perfect eyesight). So when I first saw this picture of the summit of one of the huge Martian ex-shield volcanoes, Pavonis Mons, I assumed it was a mistake; HiRISE either had the shakes or it had developed myopia.

Actually, this image is in focus, HiRISE is working perfectly. It’s the Martian surface that’s blurry…
Pavonis Mons is one of the Martian “Big Three” ancient volcanoes situated on the Tharsis bulge. Second only to Olympus Mons (the biggest volcano in the Solar System, standing at a mighty 27 km above the Martian surface), Pavonis Mons certainly isn’t small. It reaches 16 km into the Martian skies where the air is so tenuous, it barely reaches a pressure of 130 Pa (compared with the 600 Pa mean surface pressure of Mars), that’s 0.1% the average sea-level pressure on Earth.

When you have an atmosphere so thin at such high altitudes, there are consequences. In the case of this HiRISE image, the issue is that the summit of Pavonis Mons becomes rather blurred.

During major dust storms on the planet, huge quantities of dust can be deposited at the tops of these tall volcanoes, covering them in a thick layer. When the wind blows, it lacks the muscle of the thicker atmosphere found 16km below, so less dust is picked up and transported away. Although small ripples in the dust can be seen (highlighting the fact that there is a weak wind blowing up there), it doesn’t carve definite shapes into the regolith. Instead, it leaves a thick layer of fluffy, smooth dust to collect. When images are taken from space, it has a blurry appearance.

In case you don’t believe me, look at this high resolution version of the image above, zooming into the top right-hand corner where you’ll see a small, recent (and in-focus) impact crater. Also, look at the focused ripples in the dust on the lighter northern edge of the volcano.